EAU CLAIRE, Wis. (AP) — Playing to a younger audience, Vice President Joe Biden stressed differences Thursday between the presidential campaigns on education, college debt and entitlement programs more in doubt for future generations.

The education emphasis during a stop at the University of Wisconsin-Eau Claire figures into the campaign's newfound urgency to protect a state the Democratic ticket of Biden and Barack Obama won with ease in 2008. Younger voters were a key part of their victory.

Speaking to a crowd estimated by local fire officials at 3,000 people, Biden highlighted tax credits, grant programs and other moves by the Obama administration to defray college costs and increase spending that schools could use to hire more teachers. He portrayed Republican presidential challenger Mitt Romney and running mate Rep. Paul Ryan as hostile to those programs.

"They hardly mention education at all except in a negative context," Biden said.

He frequently pointed to budget proposals by Ryan, the House Budget Committee chairman, that would cut spending on items like college Pell Grants.

A Romney campaign bus circled the campus where Biden appeared. Afterward, Romney spokesman Ben Sparks said he expects Republicans to make inroads among younger voters.

"All they have done is come of age in the middle of a recession," Sparks said. "More students are living at home after graduation and unemployed."

The stop was Biden's second this month, a sign of the state's new importance as an established presidential battleground.

Obama won the state by 14 percentage points in 2008 but Republicans have been on the march ever since. Both sides launched aggressive new ad campaigns in the state this week, hoping to tip Wisconsin's 10 electoral votes their way.

The vice president opened his appearance by paying tribute to U.S. diplomats overseas, particularly the four Americans killed this week at the U.S. Consulate in Libya. But he spent the bulk of his 40-minute speech criticizing the Republican ticket's domestic proposals.

He said Romney's tax plan would disproportionately benefit the wealthy. Drawing a contrast, Biden said the Democratic approach is to "promote the private sector, not the privileged sector."

Democrats at the event didn't hide their urgency. Western Wisconsin, which has vacillated between the parties in recent elections, could prove critical this time.